diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index cf441ce1..f3f10481 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -1003,7 +1003,7 @@ const Dactyl = Module("dactyl", {
      * @param {Object} error The error object.
      */
     reportError: function reportError(error, echo) {
-        if (error instanceof FailedAssertion) {
+        if (error instanceof FailedAssertion || error.message === "Interrupted") {
             if (error.message)
                 dactyl.echoerr(error.message);
             else
diff --git a/common/content/events.js b/common/content/events.js
index f0cfa5ff..f641a7f7 100644
--- a/common/content/events.js
+++ b/common/content/events.js
@@ -251,7 +251,6 @@ const Events = Module("events", {
 
             for (let [, evt_obj] in Iterator(events.fromString(keys))) {
                 for (let type in values(["keydown", "keyup", "keypress"])) {
-                    let elem = dactyl.focus || buffer.focusedFrame;
                     let evt = this.feedingEvent = update({}, evt_obj, { type: type });
 
                     if (isObject(noremap))
diff --git a/common/content/io.js b/common/content/io.js
index 83362f39..0bc2de62 100644
--- a/common/content/io.js
+++ b/common/content/io.js
@@ -265,7 +265,16 @@ lookup:
         let process = services.create("process");
 
         process.init(file);
-        process.run(blocking, args.map(String), args.length);
+        process.run(false, args.map(String), args.length);
+        try {
+            if (blocking)
+                while (process.isRunning)
+                    util.threadYield(false, true);
+        }
+        catch (e) {
+            process.kill();
+            throw e;
+        }
 
         return process.exitValue;
     },
@@ -588,19 +597,20 @@ lookup:
                 if (args.bang)
                     arg = "!" + arg;
 
-                // replaceable bang and no previous command?
-                dactyl.assert(!/((^|[^\\])(\\\\)*)!/.test(arg) || io._lastRunCommand,
-                    "E34: No previous command");
-
                 // NOTE: Vim doesn't replace ! preceded by 2 or more backslashes and documents it - desirable?
                 // pass through a raw bang when escaped or substitute the last command
 
                 // This is an asinine and irritating feature when we have searchable
                 // command-line history. --Kris
-                if (options["banghist"])
+                if (options["banghist"]) {
+                    // replaceable bang and no previous command?
+                    dactyl.assert(!/((^|[^\\])(\\\\)*)!/.test(arg) || io._lastRunCommand,
+                        "E34: No previous command");
+
                     arg = arg.replace(/(\\)*!/g,
                         function (m) /^\\(\\\\)*!$/.test(m) ? m.replace("\\!", "!") : m.replace("!", io._lastRunCommand)
                     );
+                }
 
                 io._lastRunCommand = arg;
 
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index 126ab13f..d3ce56ab 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -38,7 +38,10 @@ if (!Object.defineProperty)
         if ("value" in desc)
             if (desc.writable && !objproto.__lookupGetter__.call(obj, prop)
                               && !objproto.__lookupSetter__.call(obj, prop))
-                obj[prop] = value;
+                try {
+                    obj[prop] = value;
+                }
+                catch (e if e instanceof TypeError) {}
             else {
                 objproto.__defineGetter__.call(obj, prop, function () value);
                 if (desc.writable)