Easiest way to get to 10 million XP
Instead of fighting the pandas on destroyed streets and fighting sullivan on agency HQ.
In the level Asylum when you fight the SwordPig if you stack all the extra XP abilities and use explosive limbs. you knock down the sword pig and it'll give you 48,000! XP and it literally takes one minute to defeat it once you get used to it. just slash it's ass an it's limbs will fall off and it'll stay down. Plus use explosive limbs to knock it down.