Multikills!

Taxonomy upgrade extras: 

Kill 10 opponents within 4 seconds of the previous kill.

Kill 9 opponents within 4 seconds of the previous kill.

Kill 8 opponents within 4 seconds of the previous kill.

Kill 3 opponents within 4 seconds of the previous kill.

Taxonomy upgrade extras: 

Kill 4 opponents within 4 seconds of the previous kill.

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Kill 6 opponents within 4 seconds of the previous kill.

Taxonomy upgrade extras: 

Kill 5 opponents within 4 seconds of the previous kill.

Taxonomy upgrade extras: 

Kill 7 opponents within 4 seconds of the previous kill.

Taxonomy upgrade extras: 

Kill 30 opponents in a row without dying.

Taxonomy upgrade extras: 

Kill 2 opponents within 4 seconds of the previous kill.

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