Symptoms

I designed a workflow to capture input from 4 different users. So I configured the escalation on the Activity level to go to same activity which worked but the other activities are completing when the escalation happens.
 

Diagnoses

This behavior that you are seeing is as expected when performing a GotoActivity in a process that contains parallel activities/client events. "If the Goto activity action is performed, all active and running state activities and lines will expire and any further executions will cease before the process will go to the activity as specified" this will also applies to any other parallel activities/client events that are waiting for use action.

http://help.k2.com/onlinehelp/k2blackpearl/userguide/current/webframe.html_EscW12.html

1. If possible, perhaps using sequential activities/client event will also achieve what you are attempting to accomplish.

2. Alternatively, if the use of parallel event is necessary then perhaps using just an 'Email Escalation' is necessary to keep the parallel activities/events active.

http://help.k2.com/onlinehelp/k2blackpearl/userguide/current/webframe.html_EscW07.html

3. Depending on what you are attempting to accomplish, perhaps using a parentchild process (IPC) implementation is also possible.
 

Resolution

'Email Escalation' was used instead to 'Goto Activity' escalation to prevent parallel activities from expiring. The 'ActivityInstanceDestinationUserEmail' field is only available when using 'Advanced' Destination Planning with the 'Plan Per Destination' option. To enable advanced destination planning > launch the destination planning configuration wizard > select 'Back' > then check the 'Run this wizard in Advanced Mode' > select the "Plan per destination" > "All at once" option.

Information regarding Advanced mode can be found in the following white paper:
http://help.k2.com/advanceddestinations_whitepaper.aspx