After three training sessions, the Rebels returned to action with a squad of 19 players, all of whom got minutes under their belt, including trialists Bradley Clayton and Bilal Sayoud.
Clayton went close early on and even closer on nine minutes when he was set through on goal, but the Met goalkeeper turned his effort onto a post.
Chris Flood headed just wide and Harrison Gilkes was also denied – but the visitors went ahead against the run of play on 17 minutes.
Just a minute later, Slough were level as Clayton made space for himself before smashing home from the edge of the box.
Sayoud impressed in spells and went on a run before putting a snapshot narrowly wide, and shortly before half time he put another long shot just off target.
Simon Dunn rattled the Met Police crossbar on 39 minutes with a superb strike which sailed over the keeper before rebounding to safety.
There were changes aplenty at the break, with the visitors fielding a different eleven and Slough introducing all eight of their substitutes.
James Dobson saw a free kick easily held, whilst Manny Williams had an effort blocked.
Slough went close on several occasions, with Lee Togwell having a header cleared off the line and Perry Coles putting a shot wide. The score remained at 1-1 until the 74th minute, when Josh Jackman won a corner from which Lee Togwell headed in to give the Rebels the lead.
Almost immediately, Met Police equalised with a stunning strike from around 25 yards to make it 2-2.
Two late goals sealed the win for Slough in what was a good workout. Louie Soares played in Coles, whose shot was saved but Lee Togwell followed up.
In the final minute a mix-up in the Slough defence allowed Coles the chance to lob the Met Police keeper to make it 4-2.
Slough Town Line up
Jack Turner, Sean Fraser, George Wells, Guy Hollis, Mark Nisbet, Scott Davies, Bilal Sayoud, Simon Dunn, Bradley Clayton, Chris Flood, Harrison Gilkes. Substitutes (all used): Josh Jackman, Lee Togwell, Matt Day, Sam Togwell, James Dobson, Louie Soares, Perry Coles, Manny Williams.