If you're using modern browsers (particularly IE10 or higher), you could use
the formtarget
attribute[
^] on your button:
<input class="starrtexam" type="submit" value="End Exam" name="submit" formtarget="_parent" />
Otherwise, you'll need to return a view which uses Javascript to change the location of the parent frame:
<noscript>
<a href="@Url.Action("Login", "Account")" target="_parent">Continue...</a>
</noscript>
<script>
parent.location.assign('@Url.Action("Login", "Account")');
</script>