Dang, that's confusing.
I think you are trying to ask a question concerning your employment while you are in college? Not sure how /any/ college job would be considered a "stepping-stone" to law enforcement unless it is law enforcement related...and if it's law enforcement related and you are in college, I'm sure they naturally assume that you plan on attempting to further your career with your degree...otherwise why would you be in college?
If it's not law enforcement related...do like I did, explain to them your plans and hopes of becoming a LEO and when your BI get started let them know to expect a call. Give them notice after you get accepted to the academy (2 weeks prior to the start of the academy..or 2 weeks after you recieve notification if they have an internship program for academy attendees). That is generally accepted etiquette for leaving a job. They sure as hell aren't going to fire you for wanting to find a new career, and if they do...well I would have an attorney on their *** quick as Dale Jr. on race day!
If the question is concerning leaving Houston PD for a higher level agency or better paying agency...then yeah, what the previous poster said. I plan on, if I am accepted into the Texas DPS, staying on with them for five or six years and then looking towards a federal appointment...I ran this by my BI and he said typically if Troopers are going to move on they do it after 5 or 6 years...just depends on the agency.
"Improvise, Adapt, Overcome"
TX DPS
Application Turned in (05/30/08)
Written Tests - PASSED (05/30/08)
Background Investigation - PASSED (06/08/08)
Oral Board - PASSED (06/26/08)
Conditional Job Offer/Testing:
USBP
Written Test: Passed (06/28/08)
Tentative Job Offer: Accepted & Forms Returned
Local PD
Civil Service Exam: Passed (06/28/08)
Agility Test: Passed (07/02/08)
BI: