in workflow Need to stop sc task creation after approval or rejected within timeline if userapproved

[Purushotham Ga2]

we created a SR form 'Admin account disabled by AD automation due to inactivity1' and attached the workflow'Account Disabled by AD Automation '.
requirement: we were add a BRANCH activity --> then added 2 activities
like 1 is timer for 15 min-- if manager not approved within timer then it willl create sc task
2 is manager approval -->if manager approved within 15 min then one sc task should create and need to cancel/ignore the timer and should not create sc task.
3 is manager rejected also need to create sctask but after approved or rejected also timer related sc task getting created
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after 15 min, manager should not able to approve that request.

please assist me on this

[Purushotham Ga2]

 var gr = new GlideRecord('sysapproval_approver');

    gr.addQuery('sysapproval',current.sys_id);

    gr.addQuery('state','requested');

    gr.query();

    while(gr.next())

    {

        gr.state = "skipped";

                gr.comments = "Auto approving the approval after 5 minutes.";

        gr.update();

                workflow.scratchpad.abc=5;

    }

[Purushotham Ga2]