Translation:You are policemen, are you hurrying here too?
How do these 2 clauses go together, in any language? I'm pretty sure the police already know they are police and don't need to be told... It makes no sense.
Maybe the policemen were so shocked at what happened that they forgot about their duty for a moment. Or maybe the speaker states that first clause more to himself than to those he's talking to: "hm, yeah, you're policemen..."
Because in the Hungarian sentence the two clauses are independent. They could function as separate sentences as well: "Rendőrök vagytok. Idesiettek ti is?"
Your sentence would be better translated as "Rendőrök vagytok, akik idesietnek?" where a subordinate clause is used to fill the role of the participle "hurrying".
Idesiettek looks like past tense. If it is with to tt in present tense, then how many tt's will it have in past tense?
That's a tricky one, because "siettek" means both "you're hurrying." (plural you) and "they hurried".
Present - past
(Én) Sietek. - Siettem.
(Te) Sietsz. - Siettél.
(Ő) Siet. - Sietett.
(Mi) Sietünk. - Siettünk.
(Ti) Siettek. - Siettetek.
(Ők) Sietnek. - Siettek.
In written, it is decided by the question mark / period. In spoken, it is decided by the intonation. Indicative (.) mood is marked with descending intonation. Interrogative (?) mood is marked with either "ascending-but-ending-with-sudden-fall" intonation (used when there is no question word) or "descending-but-ending-with-sudden-rise" (used when there is a question word)
eg1. idesiettek ti is? --> it is ascending until ti, but is is toned low.
eg2. miért siettek ide? --> it is descending until the i in ide, but de is toned high.