Remember when, last summer, Brian explained to you what surplus value is? Well, this is in the same arena: an employer will take a mile if you give them an inch. As a matter of fact, I think you will be very lucky if Karthik ever lets you leave. Adding a contigency would have given you (and us) more flexibility. Karthik may not be willing to add an end date at all because you'll be working for him "at will". You'll probably just have to decide when you want it to end.