
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given points A(0, 1), B(0, -1), and a moving point P, such that the product of the slopes of lines PA and PB is $- \frac {1}{2}$.  
(Ⅰ) Find the equation of the trajectory C of the moving point P;  
(Ⅱ) Let Q(2, 0), and a line l passing through point (-1, 0) intersects C at points M and N. Let the area of $\triangle QMN$ be denoted as S. If for any line l that satisfies the conditions, the inequality $S \leq \lambda \tan MQN$ always holds, find the minimum value of $\lambda$.

Present the answer in LaTex format: \boxed{Your answer}
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